I did know that, but wasn't sure the "p" stood for "perl". The manual page for preg_match leads with "preg_match — Perform a regular expression match", so I went with that.

True, and you never know with PHP.

The preg functions are wrappers around the Perl Compatible Regular Expressions library, though (PCRE) vs the older POSIX greg PHP functions, so I do think they mean Perl.